Highly selective resonance scattering detection of trace thrombin using aptamer-modified AuRe nanoprobe

The gold-rhenium (AuRe) composite nanoparticle was prepared by NaBH(4) reduction procedure, and was modified by the aptamer to obtain an AuRe nanoprobe (AuRessDNA) for thrombin. In pH 7.0 Tris-HCl buffer solution and in the presence of salt, the nanoprobe specifically combined with thrombin to form AuRe-aptamer-thrombin cluster that resulted in the resonance scattering intensity (I (560 nm)) increasing at 560 nm. The increased intensity ΔI (560 nm) was linear to the thrombin concentration in the range of 0.115-6.93 nmol/L, with a regression equation of ΔI (560 nm) = 53.0 C + 2.5, a correlation coefficient of 0.9989, and a detection limit of 13 pmol/L. This method was applied to detect thrombin in human plasma samples, with satisfactory results.